Server setup script for Redis, HAProxy and Node.js

I wrote a pretty basic setup script that handles most of the setup for a Three-server solution. The solution and setup file are available on GitHub

The three servers are Redis, HAProxy and Node / Cron.

All three options handle only solution specific stuff (not including installing the frameworks)

I felt like my usage of select statements was a little over the top, and newline as a constant seemed a little hacky, but nonetheless, it works.

```
n="
"
# From http://stackoverflow.com/a/246128
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
pass (){
echo $1 | sha256sum | head -c 64
}

# Redis
redis (){
ulimit -n 10032
slave=false;
echo "Enter the desired password for the Redis instance:"
read -s password
password=$(pass $password)
echo "Is this a slave?"
select yn in "Yes" "No"; do
case $yn in
Yes ) slave=1; break;;
No ) slave=0; break;;
esac
done
slave_text="";
if [[ $slave -eq 1 ]]; then
echo "Enter the Master IP address:"
read master_ip
echo "Enter the Redis Master password:"
read -s master_password
slave_text="slaveof $master_ip 6379
masterauth $master_password $n"
fi
echo "tcp-keepalive 60
port 6379
tcp-backlog 511
timeout 600
dir $DIR
supervised upstart
daemonize yes
#bind 127.0.0.1
maxmemory-policy noeviction
requirepass $password
$slave_text
" > "/etc/redis/redis.conf"
echo "The password for Redis is $password"
sudo service redis restart
}

# HAProxy
haproxy (){
stats=1;
stats_text="stats disable$n";
echo "Please enter the IP address of the web server:"
read initial_ip
echo "Please enter the port of the web server:"
read initial_port
i=1
web_servers="server web$i $initial_ip:$initial_port check$n"
more_web_servers=1;

while [ $more_web_servers -eq 1 ]
do
echo "Would you like to add another web server?"
select yn in "Yes" "No"; do
case $yn in

shellcheck it!

There is this wonderful site called shellcheck.net that tells you all kinds of common mistakes.

The newline in a string

n="
"

n is an unusual name for something that's a newline. How about newline?

Here's another writing style that you might like:

n=

For more details on this syntax, search for \$' in man bash.

Embedding variables in a string

The linebreak is odd in the middle of the string,
especially considering the $n variable that you have:

slave_text="slaveof $master_ip 6379
masterauth $master_password $n"


I'm wondering if you didn't use $n because you were not sure how to make it work. Here are some equivalent ways to write the statement on a single line:

slave_text="slaveof $master_ip 6379${n}masterauth $master_password $n"
        slave_text="slaveof $master_ip 6379$n""masterauth $master_password $n"


Embedding variables in text

This is very tedious, as you had to escape all the ":

echo "{
    \"redis\": {
        \"current_environment\": \"prod\",
        \"environments\": {
            \"prod\": {
                \"host\": \"$redis_master_ip\",
                \"port\": \"6379\",
                \"password\": \"$redis_master_password\"
            }
        }
    },
    \"haproxy\": {
        \"IP\": \"$HAProxy_IP\"
    }
}" > "$DIR/web.config.json"


A simpler approach would have been to enclose in single quotes instead,
and break out of it in front of variables, like this:

echo '{
    "redis": {
        "current_environment": "prod",
        "environments": {
            "prod": {
                "host": "'$redis_master_ip'",
                "port": "6379",
                "password": "'$redis_master_password'"
            }
        }
    },
    "haproxy": {
        "IP": "'$HAProxy_IP'"
    }
}' > "$DIR/web.config.json"


But an even better way is to use a here-string:

cat  "$DIR/web.config.json"
{
    "redis": {
        "current_environment": "prod",
        "environments": {
            "prod": {
                "host": "$redis_master_ip",
                "port": "6379",
                "password": "$redis_master_password"
            }
        }
    },
    "haproxy": {
        "IP": "$HAProxy_IP"
    }
}
EOF


Redirecting both stdout and stderr

Instead of this:

npm install -g webpack gulp > /dev/null 2 >&1


A simpler way to redirect both stdout and stderr is this:

npm install -g webpack gulp &> /dev/null


The shebang

Don't forget to start your script with the correct shebang:

#!/usr/bin/env bash


Inconsistent use of [ and [[

In some places you use [ and in others [[.
I think it will be slightly easier to read the script if you used a consistent writing style.
[ is considered obsolete, [[ is recommended.

Trailing ;

A ; at the end of a line is pointless (unless it's part of a ;; in a case statement). I suggest to remove those.

Tedious -eq

The -eq operator is kind of tedious here:

if [[ $slave -eq 1 ]]; then


A simple = would work just as well, so I recommend to write that way.

Writing style

This is a bit unusual:

pass (){


A more common writing style is this:

pass() {
\n'

For more details on this syntax, search for \$' in man bash.

Embedding variables in a string

The linebreak is odd in the middle of the string,
especially considering the $n variable that you have:

%%CODEBLOCK_2%%

I'm wondering if you didn't use $n because you were not sure how to make it work. Here are some equivalent ways to write the statement on a single line:

%%CODEBLOCK_3%%

Embedding variables in text

This is very tedious, as you had to escape all the ":

%%CODEBLOCK_4%%

A simpler approach would have been to enclose in single quotes instead,
and break out of it in front of variables, like this:

%%CODEBLOCK_5%%

But an even better way is to use a here-string:

%%CODEBLOCK_6%%

Redirecting both stdout and stderr

Instead of this:

%%CODEBLOCK_7%%

A simpler way to redirect both stdout and stderr is this:

%%CODEBLOCK_8%%

The shebang

Don't forget to start your script with the correct shebang:

%%CODEBLOCK_9%%

Inconsistent use of [ and [[

In some places you use [ and in others [[.
I think it will be slightly easier to read the script if you used a consistent writing style.
[ is considered obsolete, [[ is recommended.

Trailing ;

A ; at the end of a line is pointless (unless it's part of a ;; in a case statement). I suggest to remove those.

Tedious -eq

The -eq operator is kind of tedious here:

%%CODEBLOCK_10%%

A simple = would work just as well, so I recommend to write that way.

Writing style

This is a bit unusual:

%%CODEBLOCK_11%%

A more common writing style is this:

%%CODEBLOCK_12%%

StackExchange Code Review Q#136187, answer score: 2